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Accelerator pump tuning

Cornpatch MO said:
At what point should a person consider going to a 50cc acc. pump on the secondary? Assuming timing and advance curve is right. Trying to get the big bog out at under 2000 rpm( 4 speed) And I can't get enough gas through the mechanical secondaries to make black exhaust smoke. ........................MO
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From what I have read in the singe book that I have, over 700 hp before you need the 50cc.
I'm thinking that lewtot184 might be on to something with too much fuel being my problem. When I floor the pedal at idle -1500rpm, my A/F gauge goes rich until it hits 2500. Then all is well. Anybody know where I should concentrate next? From the way I am interpreting my book, the power valve jets are the place to fix this?
 
Thought I should update this thread with thanks to all that gave suggestions. Finally got this thing running like a raped ape! Ended up buying a couple of out of print tuning books that helped immensely. I seriously don't know how anybody can tune a car precisely without an air/fuel meter, I used am AEM X series 30-0300. Found out that my lean blip when stepping on the gas was actually caused by my power valve being to low. Changed that from a 4.5 to a 6.5. Then downsized my secondary jets from 80 to 78, and my primary jets from 71 to 70. Primary pump cam is white in #1 hole with a 31 squirter, and secondary cam is red in #1 hole with a 33 squirter. Also hooked my vacuum advance back up to the ported tap 18-34-47 all in at 3400. Amazing that just a few small changes can take a car from being almost undrivable to one that you don't want to get out of.
 
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When I had the Holley 870 Avenger on my car is was the same deal, 4.5 power valve? Switched it to a 6.5 and it made a world of difference.
 
747mopar said:
When I had the Holley 870 Avenger on my car is was the same deal, 4.5 power valve? Switched it to a 6.5 and it made a world of difference.
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Don actually had me using a 3.5 before the 4.5, his recommendations were going the wrong way. So glad I spent the time to learn about this tuning for myself. Now I have 2 more cars that I know I can get to run even better than they are now :thumbsup:.
 
By the way, are you going to the Nats this year?
 
hunt2elk said:
From what I have read in the singe book that I have, over 700 hp before you need the 50cc.
I'm thinking that lewtot184 might be on to something with too much fuel being my problem. When I floor the pedal at idle -1500rpm, my A/F gauge goes rich until it hits 2500. Then all is well. Anybody know where I should concentrate next? From the way I am interpreting my book, the power valve jets are the place to fix this?
Click to expand...
Did you happen to notice if you had black exhaust smoke when your A/F gauge showed rich at those lower rpm 's ? ............................MO
 
hunt2elk said:
By the way, are you going to the Nats this year?
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Most likely I'll be going with my girl, that's the 1 show I try to get to every year.

I'm really surprised about Don, I ordered my Quickfuel from him tuned to my engine and it's flawless. Best carb I've ever owned honestly.
 
Cornpatch MO said:
Did you happen to notice if you had black exhaust smoke when your A/F gauge showed rich at those lower rpm 's ? ............................MO
Click to expand...
I never noticed any black smoke out the back during any of this. All 3 of the tuning books I have did mention that as an indicator to try smaller squirters though.
 
747mopar said:
Most likely I'll be going with my girl, that's the 1 show I try to get to every year.

I'm really surprised about Don, I ordered my Quickfuel from him tuned to my engine and it's flawless. Best carb I've ever owned honestly.
Click to expand...

I am hoping to free up enough time to make the trip this year, will let you know. Your daughter must be getting close to driving age?
Yeah, I don't know about Don anymore. I think he is getting burned out. A lot of personal issues with both himself and his wife. This carb came from him as well, just not set up for my motor like he told me it would be. It was sent back to him twice. The distributor for this car that he sold me was sent back to him 4 times before being thrown in the scrap pile. I do like his control boxes though and use them on all my cars. I also really like these Quick Fuel carbs and even spec'd one out for the last motor I had built. Don doesn't sell them anymore. Of course he says they are junk now, when before you could buy no better. I do have stuff from him on my Charger, and that has been fine. Although after what I went though on this car I know there is a lot of power left on the table which I will address this summer.
 
hunt2elk said:
I am hoping to free up enough time to make the trip this year, will let you know. Your daughter must be getting close to driving age?
Yeah, I don't know about Don anymore. I think he is getting burned out. A lot of personal issues with both himself and his wife. This carb came from him as well, just not set up for my motor like he told me it would be. It was sent back to him twice. The distributor for this car that he sold me was sent back to him 4 times before being thrown in the scrap pile. I do like his control boxes though and use them on all my cars. I also really like these Quick Fuel carbs and even spec'd one out for the last motor I had built. Don doesn't sell them anymore. Of course he says they are junk now, when before you could buy no better. I do have stuff from him on my Charger, and that has been fine. Although after what I went though on this car I know there is a lot of power left on the table which I will address this summer.
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It wouldn't surprise me if they are junk now? I bought a Demon years ago before Holley bought them out and really liked it, fast forward to my Charger where I bought another Demon (post Holley) and it was noticeably cheaper. I checked to see if what he told me was correct and yes Holley bought Quickfuel as well. Although Holley makes great cards I hate that company with a passion, everytime a company steps up and offers a better product for your money they snatch them up to keep their monopoly.

The daughter is 11 going on 12 and already has a 72 Sattelite waiting it's turn.:thumbsup:
 
hunt2elk said:
I think most run theirs locked at 35 or whatever they want, but then have the ignition wired up to get the motor spinning, then flip a switch to let the spark come through.
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I run mine locked at 32 degrees and run a start retard on the MSD ignition.
 
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